The world isn’t short of apps that rethink email (Mailbox, Mailpile, Boxer and Mail Ninja are among those that spring to mind), but Cate, from Swiss outfit River, is a concept for a really simple messaging solution that could be really compelling if it ever sees the light of day.

Currently raising money on Indiegogo, Cate promises to support the likes of Gmail, Twitter, Facebook Chat and App.net in a unified messaging app that combines smart keyword analysis with an elegant, minimalist and predictably flat-design. We’d love to give it a go, but with only $121 raised towards its $140,000 goal at the time of writing, it certainly needs a push to get there.